Lambswool leaves a lot of hair behind, even if you use methods to remove loose hairs. For smaller floors we used a water base applicater. The concern is that the oil-base eats up the foam, but for smaller floors it is preferred because it does not shed hairs. Of all the times I used one, there was never an issue of the foam deteriorating. A smaller floor is finished quickly, and the foam doesn't have time to deteriorate. Just be careful not to skip, because applicator does not hold as much urethane as lambswool.
Have one person with a brush cutting in edges and keeping wet edges if necessary, and the other using the applicator.
Have used a lot of Zar oil base of different sheens, results are nice. First few coats with sand N' seal, and then last few coats with Ultra.
Regardless of what product and application you use, keeping a wet edge is key. No furniture should go on it for at least 7 days.
Remember to wear good masks, stuff is awful to breathe.
To avoid bubbles, stir, never shake. Also when applying, move at a steady pace, not too fast. Plopping, and fast moving create bubbles. Also, you can thin it down (with thinner) so that bubbles pop easier, but that may dull the sheen a tiny bit.