What expansion gap do you use for 5/16" thick Bruce solid hardwood? This is upstairs, no special situations. The only moisture issue would be if the roof leaks. 11x16 room.
The installation instructions show 3/4" perimeter which seems extremely excessive for 5/16 flooring. The instructions show a picture of transitions and wall moldings that only have 1/4" gap including 1/4 round.

Second question, what lengths of staples work the best assuming one layer of 15# felt. I have 1-1/2" 1/4" crown but seems a bit long for the wood.

Third question, do Senco 1/4" crown staples work in the Bostitch ehf1838k? I have a box of staples but I haven't purchased a stapler yet.

Fourth question, is the Wen stapler any good from Home Depot? I prefer Bostitch but $60 vs $200 for a 160 ft^2.

From the instructions:
Always allow a minimum 3/4ʺ (19 mm) expansion around all vertical obstructions.

I installed Bruce 3/4 oak flooring on my main level several years ago. I left 3/4 gap nearly everywhere and that forced me to add base trim and 1/4 round to cover the large gap. This house is paneled and never had any base trim. Cutting the paneling would only gain 3/16" for expansion. No issues with that floor other than normal wear and it's been there at least 12 years. I used 30# felt under that floor but it seems too heavy for this 5/16 wood.

I just wonder who writes specifications for wood floors, sometimes.I leave a quarter inch gap between the flooring and sheet rock on my wood floors. Then without thick base board like from years past, I can cover the gap with either 5/16ths inch or half inch base or use a half by three quarter inch base shoe. The reason for expansion gap is some flooring can expand and push the wall out of plumb as this is the extreme, before the fasteners let loose. A lot of pressure can develop from wet wood that is held in a plane by thick nails until the nails let loose. A 3/4 inch gap will allow the nails to let loose with 8d fasteners before pressure develops with 3/4 inch thick flooring.
Quarter round is not made for floor trim, but is used if it is the only thing available as a last resort, ugh. When nailing quarter round the nails being angled down mis everything on the wall and sometimes penetrate the flooring, which negates the expansion since the flooring is nailed to the quarter round.
Quarter inch staples are interchangeable from one gun to another, except for 20 gauge, which are narrower.
Try the gun that you have in the budget. If you want to try the inexpensive one, be sure to get assurance that you can return it if not happy.

Thanks for the reply. I purchased the Bostitch ehf1838k 7/32" crown stapler and tested it on some maple 5/16" that was mixed in with my oak. The gun does shoot Senco 1/4 crown staples fine. I shot 1-1/2, 1-1/4, and 1 inch through the maple into old 3/4 cabinet plywood. I will likely use 1-1/4 unless I have several layers of felt in places. All sizes held very well and were difficult to remove. A bit surprised the gun doesn't have a depth adjustment. I had to take the pressure to 100 to set the staples correctly. Hopefully it will be consistent once I get rolling. That's why I decided on the Bostitch, afraid the Wen would be inconsistent. I see what you mean about the 1/4 round. I remember seeing the nails in the expansion gap. I will probably just use a piece of the flooring for the spacing around the perimeter. I'll make my own trim and transitions with some stock I have. The price on base molding is ridiculous right now.