I would like to change the default pool parameters. Is the unit in the fields below in BTC or the altcoin I am trading in that pool (except where its percentages, obviously)?

Limit is expressed always as PartnerCurrency (BTC in your CASE)
Reuse % is expressed as PartnerCurrency (% Will be applied on TOTAL Value, so QTY X PRICE)
Never Create is applied on QTY
PUT % IS expressed as the COIN you see in the label (MAID or BTC in that case).
When % Parameter is applied on MAID (ex PUT 1% if your MAID, you have 200 MAID so 2 MAID will be put into pool) CAT will automatic calculate the price of 2 MAID x Current Market Price = 2 MAID Value expressed as BTC. BUT you must set a QTY value for that parameter.