HSMP to Tier1, extension before 1 month of expiry

[unileeds]

Hi, Thanks to this forum, I got my HSMp stamped for 2 yrs just 1 month b4 tier1 came to the UK. In hindsight, I would have qualified for Tier1 as well, and would have got 3yr stay. I have already finished 2 yrs on a WP previous to this, and this would have given me a clear path to ILR!!

Now I want to switch to Tier 1 as soon as possible!! I still qualify!!
1. Can I switch to Tier 1 say in 2-3 months, even though I'll have roughly 17months or so left on my HSMP?
2. If I do switch, will it be treated as an extension or will it be treated as a new application? in other words do I get a 3yr visa or a 2yr visa?
3. Finally!! if i do switch at the end of HSMP do I get a 2yr or 3 yr visa? I ideally want the 3 yr visa, cause of the constant rules changes, you never know when ILR is raised to 6 yrs??

Another thing, what is the clear line with the amount of time spent outside the country while on HSMP!! wrt to ILR. I have a job that makes me travel all over the world (typical tech sales)... I do try and get company letters that state that I need to go for such and such reason for 1 week!! Technically I am emplyed, and paying tax, and have a house and everything!! how does this affect the ILR!!! I am sure I will be outside the country for more than 180 days in 5 yrs!! But most of it is work!!!

[unileeds]

looks like its a tough question then!! I realise these are still initial stages of the Tier 1 but any1 with any thoughts or opinions would be great!!