55.2-59 need to buy heater...defrost?? advice

[Missyblue]

Hello, frosty mornings are coming before i know it and i need a heater and worried about defrost. I had chosen a unit from vintage air due to previous recommendations and what they offer. the unit offered heat/ac/and defrost as an underdash unit. Sadly they are currently unavailable and no clue when or if they will be back..so asking again for experience with aftermarket companies and effectiveness? also trying to decide if no defrost is gonna be a mess in colorado weather? The cab is small so wondering if the heater will warm it enough to not need defrost....truck is not garage stored.
1st. choice for options
https://www.vintageair.com/custom/pr...pn=11300-VUZ-A

2nd choice for looks if defrost cant happen
https://www.vintageair.com/custom/pr....php?pn=674013

1. recommended companies? and or units?

2. wondering if anyone ever spliced the heater hoses somehow to add defrost? hard for me to imagine without having the units and materials in hand so maybe I'm insane haha